Atrial Fibrillation - cause and treatment

Atrial Fibrillation

What is it?

Atrial fibrillation (AF) is a condition in which the heart beats with an abnormal or irregular rhythm. When the heart beats rapidly and irregularly, serious problems can occur such as blood clotting. The abnormal rhythm can come and go (called paroxysmal atrial fibrillation), persist for longer than 7 days (persistent atrial fibrillation), or persist despite treatment (permanent atrial fibrillation).

Atrial Fibrillation

What causes it?

The heart muscle has four chambers or compartments. The two upper chambers are called the right and left atria. Within the right atria, is a small mass of tissue - known as the sinoatrial node (SA node). This SA node triggers an electrical - like impulse that stimulates the heart muscle to beat and pump blood in and out of the heart. The SA node is like a “pacemaker” for the heart. It controls how fast the heart beats and keeps the rhythm of the heart regular.

For most individuals, when the heart beats at a normal rate and rhythm, it pumps about 60 to 100 times per minute. Atrial Fibrillation (AF) can cause the heart to beat 120 to 180 times per minute, or faster. When AF occurs, electrical impulses originate from many areas in the atrium instead of from the SA node - as many as 350 different impulses per minute, all trying to cause the heart to beat. Unfortunately, the heart cannot respond to the overload of electrical - like impulses and thus it begins to beat rapidly and irregularly - almost like a quiver instead of a beat. The fast and irregular beating of the heart can cause the feeling of heart fluttering or palpitations. Additionally, blood is not pumped effectively and may pool in the atria. When blood pools, it is more likely to clot. If a clot develops and breaks loose it can clog a blood vessel in the brain, causing a stroke.

The two lower chambers - the right and left ventricles - of the heart are also affected by AF. Rapid and irregular beating does not allow sufficient time for the ventricles to adequately fill with blood before being stimulated to pump the blood out of the heart again. As a result, less blood is pumped out of the heart and the body’s tissues--which are dependent on the heart for oxygen-rich blood--are provided with a smaller supply, causing symptoms like shortness-of-breath, dizziness and fatigue or tiredness.

Coronary Heart Disease

Coronary heart disease, also termed coronary artery disease or ischaemic (ischemic) heart disease, is the most common form of heart disease and the most common cause of death in the western world. The coronary arteries are large blood vessels in the surface of the heart that deliver blood to the heart muscle. Fatty plaques can build up in the arteries and block blood flow - a process called atherosclerosis. If the arteries become blocked, the heart muscle does not get enough oxygen, bringing on a variety of symptoms such as chest pain and shortness of breath, as well as heart muscle damage and even death.

The main mechanisms of angina (chest pain) are conditions that either decrease the supply of blood, or increase the demand for blood. Decreased supply is most commonly due to atherosclerosis (a build up of fatty deposits), or spasms in the arteries, which can limit the space through which blood flows to the heart.

An increase in demand takes place during exercise or exertion. The heart beats faster to supply the muscles and other organs with more oxygen in response to the increased demand. Chronic stable angina results when this increased demand for blood exceeds the supply to the coronary arteries. This can also occur during periods of stress, or extreme temperatures. Although spasms of the coronary arteries are the main cause of Prinzmetal's angina, approximately two thirds of people with this type of angina also have atherosclerosis in at least one vessel.

Coronary heart disease can result in:
* Angina pectoris
* Unstable Angina
* Acute myocardial infarction, or heart attack

There is no exact single cause of coronary heart disease but rather numerous factors that can contribute to or increase the risk of developing the condition. These factors can include lifestyle, heredity, age, and gender.